在后台将字节转换为INT64

Question

Good day. For a current project I need to know how datatypes are represented as bytes. For example, if I use :

long three = 500;var bytes = BitConverter.GetBytes(three);

I get the values 244,1,0,0,0,0,0,0. I get that it is a 64 bit value, and 8 bits go int a bit, thus are there 8 bytes. But how does 244 and 1 makeup 500? I tried Googling it, but all I get is use BitConverter. I need to know how the bitconverter works under the hood. If anybody can perhaps point me to an article or explain how this stuff works, it would be appreciated.

Answer 1

It's quite simple.

BitConverter.GetBytes((long)1); // {1,0,0,0,0,0,0,0};
BitConverter.GetBytes((long)10); // {10,0,0,0,0,0,0,0};
BitConverter.GetBytes((long)100); // {100,0,0,0,0,0,0,0};
BitConverter.GetBytes((long)255); // {255,0,0,0,0,0,0,0};
BitConverter.GetBytes((long)256); // {0,1,0,0,0,0,0,0}; this 1 is 256
BitConverter.GetBytes((long)500); // {244,1,0,0,0,0,0,0}; this is yours 500 = 244 + 1 * 256

If you need source code you should check Microsoft GitHub since implementation is open source :) https://github.com/dotnet

Answer 2

From the source code :

// Converts a long into an array of bytes with length 
// eight.
[System.Security.SecuritySafeCritical]  // auto-generated
public unsafe static byte[] GetBytes(long value)
{
    Contract.Ensures(Contract.Result<byte[]>() != null);
    Contract.Ensures(Contract.Result<byte[]>().Length == 8);

    byte[] bytes = new byte[8];
    fixed(byte* b = bytes)
        *((long*)b) = value;
    return bytes;
}